When performing power-saving advice and automatic appliance control in accordance with a resident, there is a need for behavior (presence/absence, an action such as cooking or sleeping) of each individual person. Among these, as methods for acquiring the presence/absence, there are conventionally known methods using a surveillance camera, an IR image sensor, a floor pressure sensor, an ultrasonic sensor, a wireless tag and a reader, and the like.
Among these methods, the image camera, the IR image sensor, the floor pressure sensor and the ultrasonic sensor have a problem with privacy and costs. In relation to this, there is known a technique that uses a pyroelectric sensor and a person-number detecting sensor in combination, and by a calculation, acquires the presence/absence for each room from the information obtained by these sensors.
However, although the above technique has a problem in that although the presence/absence/unknown can be discriminated, the probabilities cannot be calculated, and a problem in that persons present in a room cannot be distinguished from each other.